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Remote sensing; the XIIIth symposium of agard-nato on advanced techniques for aerospace surveillance
Photogrammetria - Elsevier Publishing Company, Amsterdam - Printed in The Netherlands
Symposium Report REMOTE SENSING; THE XIIIth SYMPOSIUM OF AGARD-NATO ON ADVANCED TECHNIQUES FOR AEROSPACE SURVEILLANCE G. P. DE LOOR
Physics Laboratory, Rijksverdedigingsorganisatie,
T.N.O., The Hague (The Netherlands)
(Received November 16, 1967)
INTRODUCTION
"Hitherto, ground surveillance from an airborne platform has been mainly performed from manned aircraft, by normal photographic means. Equipment has continually improved, but during the past ten years, new techniques have appeared which are capable of considerably advancing ground surveillance, as regards the range of illumination usable, the range of wavelengths exploited and the type of vehicle employed. New storage media and methods of handling and transmitting information have also been employed." In this way the Avionics Panel of the Advisory Group for Aerospace Research and Development (AGARD-NATO) introduced its symposium on "Advanced Techniques for Aerospace Surveillance", which was held in Milan from September 4th to 7th, 1967. The object of this symposium was "to indicate the likely trends in ground surveillance from aerospace vehicles in view of the scientific and technological progress to be expected." The following topics were discussed: PHYSICAL FACTORS
After treatment of the influence of the atmosphere on light propagation in high-altitude photography, discussions centered mainly on emissivity, reflectivity and backscatter characteristics of objects and background. Although data arc available in the literature scattered over different places and further data were also reported at this symposium, no compilation of these data is available for general use. The meeting therefore expressed the need of such a compilation and urged a coordination of efforts to obtain more detailed emissivity and reflectivity data for the whole electromagnetic spectrum from visible into microwave frequencies and more backscatter data for the microwave region. PASSIVE MICROWAVE SENSING ( c m -
and ram-waves, "passive radar")
The sensitivity of available equipment is very near the physical limit. Fairly long integration times ("shutter speeds") - - of the order of 0.1-1 sec - - are Photogrammetria, 23 (1968) 103-104
104
G . P . DE LOOR
required to obtain the necessary temperature sensitivity of only a few degrees centigrade. This makes the application of this type of equipment limited. However, the very low impairment of the results by weather as compared to radiometers for the far infra-red justify further research in this field. RADAR
During the last few years resolution of side-looking radar systems ("active radar") for ground surveillance is brought to a near ultimate, especially by the introduction of aperture synthesis which makes it possible to focus the system on objects a great distance away from the flying platform. The reproduction of the full dynamic range of the signals received requires special measures. Applications in geology, small-scale mapping and inventory of large areas are envisaged, because of the all weather capability of these systems. TV-SYSTEMS
One paper dealt with active TV-systems, describing the (pulsed) light sources and camera tubes available and/or required. Results obtained with a passive system, giving good imagery down to star light level, were also given. RECORDING AND DISPLAY
All the electronic systems discussed at the symposium require specific recording and read-out techniques. The final picture is usually presented on a cathode ray tube and recorded on film. Recent developments in cathode ray tube displays were discussed. For projection purposes modulated laser systems show promise. IMAGE HANDLING AND INTERPRETATION
The non-conventional mapping systems described at this symposium give imagery which can essentially differ from ordinary aerial photography. A fair amount of further research into the optimalization of their use and interpretation is necessary. Overoptimistic (or pessimistic) views, often based on only a few observations, ask for a critical attitude towards results presented in this field. PROCEEDINGS
The proceedings of this symposium will be edited in full by Mr W. T. Blackband (Royal Aircraft Establishment, Farnborough, Great Britain) as an Agardograph and published by Technivision, Maidenhead, Great Britain. Photogrammetria,
23 (1968) 103 104
Symposium Report REMOTE SENSING; THE XIIIth SYMPOSIUM OF AGARD-NATO ON ADVANCED TECHNIQUES FOR AEROSPACE SURVEILLANCE G. P. DE LOOR
Physics Laboratory, Rijksverdedigingsorganisatie,
T.N.O., The Hague (The Netherlands)
(Received November 16, 1967)
INTRODUCTION
"Hitherto, ground surveillance from an airborne platform has been mainly performed from manned aircraft, by normal photographic means. Equipment has continually improved, but during the past ten years, new techniques have appeared which are capable of considerably advancing ground surveillance, as regards the range of illumination usable, the range of wavelengths exploited and the type of vehicle employed. New storage media and methods of handling and transmitting information have also been employed." In this way the Avionics Panel of the Advisory Group for Aerospace Research and Development (AGARD-NATO) introduced its symposium on "Advanced Techniques for Aerospace Surveillance", which was held in Milan from September 4th to 7th, 1967. The object of this symposium was "to indicate the likely trends in ground surveillance from aerospace vehicles in view of the scientific and technological progress to be expected." The following topics were discussed: PHYSICAL FACTORS
After treatment of the influence of the atmosphere on light propagation in high-altitude photography, discussions centered mainly on emissivity, reflectivity and backscatter characteristics of objects and background. Although data arc available in the literature scattered over different places and further data were also reported at this symposium, no compilation of these data is available for general use. The meeting therefore expressed the need of such a compilation and urged a coordination of efforts to obtain more detailed emissivity and reflectivity data for the whole electromagnetic spectrum from visible into microwave frequencies and more backscatter data for the microwave region. PASSIVE MICROWAVE SENSING ( c m -
and ram-waves, "passive radar")
The sensitivity of available equipment is very near the physical limit. Fairly long integration times ("shutter speeds") - - of the order of 0.1-1 sec - - are Photogrammetria, 23 (1968) 103-104
104
G . P . DE LOOR
required to obtain the necessary temperature sensitivity of only a few degrees centigrade. This makes the application of this type of equipment limited. However, the very low impairment of the results by weather as compared to radiometers for the far infra-red justify further research in this field. RADAR
During the last few years resolution of side-looking radar systems ("active radar") for ground surveillance is brought to a near ultimate, especially by the introduction of aperture synthesis which makes it possible to focus the system on objects a great distance away from the flying platform. The reproduction of the full dynamic range of the signals received requires special measures. Applications in geology, small-scale mapping and inventory of large areas are envisaged, because of the all weather capability of these systems. TV-SYSTEMS
One paper dealt with active TV-systems, describing the (pulsed) light sources and camera tubes available and/or required. Results obtained with a passive system, giving good imagery down to star light level, were also given. RECORDING AND DISPLAY
All the electronic systems discussed at the symposium require specific recording and read-out techniques. The final picture is usually presented on a cathode ray tube and recorded on film. Recent developments in cathode ray tube displays were discussed. For projection purposes modulated laser systems show promise. IMAGE HANDLING AND INTERPRETATION
The non-conventional mapping systems described at this symposium give imagery which can essentially differ from ordinary aerial photography. A fair amount of further research into the optimalization of their use and interpretation is necessary. Overoptimistic (or pessimistic) views, often based on only a few observations, ask for a critical attitude towards results presented in this field. PROCEEDINGS
The proceedings of this symposium will be edited in full by Mr W. T. Blackband (Royal Aircraft Establishment, Farnborough, Great Britain) as an Agardograph and published by Technivision, Maidenhead, Great Britain. Photogrammetria,
23 (1968) 103 104